Method and apparatus for detection of venous pulsation

• US 20080077022A1
• Filed: 09/27/2006
• Published: 03/27/2008
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Baker, Clark R.
• Granted Patent: US 8,123,695 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

Methods and systems for detecting venous pulsation are provided. In one embodiment, a metric of the pulse shape of one or more plethysmographic signals is derived and the presence of venous pulsation is detected based on the metric of pulse shape. Examples, of metrics of pulse shape include a skew metric and a ratio of a minima-to-maxima time over a pulse period interval. In an exemplary embodiment, the presence of venous pulsation is detected based on a metric of the pulse shape of one or more plethysmographic signals and on a phase comparison of the plethysmographic signals.

Claims

1. A method for detecting venous pulsation, comprising:

deriving a skew metric for one or more plethysmographic signals; and

detecting the presence of venous pulsation based on the skew metric.

2. The method of claim 1, wherein the skew metric comprises a measure of the skewness of the derivative of one or more plethysmographic signals.

3. The method of claim 1, wherein the skew metric is processed to compensate for the typical rate-dependent changes in the skewness of arterial waveforms.

4. The method of claim 1, wherein the skew metric is adjusted based on a pulse rate.

5. The method of claim 1, wherein detecting the presence of venous pulsation comprises:

deriving a skew of the plethysmographic signal after filtering with a first set of filters; and

comparing the skew metric to the skew of the plethysmographic signal after filtering with a second set of filters .

6. The method of claim 1, comprising providing a notification of the presence of venous pulsation when detected.

7. A method for detecting venous pulsation, comprising:

deriving a ratio of a minima-to-maxima time over an entire pulse period time of one or more plethysmographic signals; and

detecting the presence of venous pulsation based on the ratio.

8. A method for detecting venous pulsation, comprising:

deriving a metric of the pulse shape of one or more plethysmographic signals;

deriving a phase comparison of the plethysmographic signals; and

detecting the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

9. The method of claim 8, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

10. The method of claim 8, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

11. The method of claim 8, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period interval of the one or more plethysmographic signals.

12. The method of claim 8, wherein detecting the presence of venous pulsation comprises combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

13. The method of claim 12, wherein detecting the presence of venous pulsation comprises comparing the venous pulsation metric to a threshold value.

14. The method of claim 8, further comprising providing a notification of the presence of venous pulsation when detected.

15. One or more tangible, machine readable media, comprising code executable to perform the acts of:

deriving a skew metric for one or more plethysmographic signals; and

detecting the presence of venous pulsation based on the skew metric.

16. The tangible, machine readable media of claim 15, further comprising code executable to perform the act of processing the skew metric to compensate for the typical rate-dependent changes in the skewness of arterial waveforms.

17. The tangible, machine readable media of claim 15, further comprising code executable to perform the act of adjusting the skew metric based on a pulse rate.

18. The tangible, machine readable media of claim 15, further comprising code executable to perform the acts of:

deriving a skew of the plethysmographic signal after filtering with a first set of filters; and

comparing the skew metric to the skew of the plethysmographic signal after filtering with a second set of filters.

19. The tangible, machine readable media of claim 15, further comprising code executable to perform the acts of providing a notification of the presence of venous pulsation when detected.

20. One or more tangible, machine readable media, comprising code executable to perform the acts of:

deriving a ratio of a minima-to-maxima time over an entire pulse period time of one or more plethysmographic signals; and

detecting the presence of venous pulsation based on the ratio.

21. The tangible, machine readable media of claim 20, further comprising code executable to perform the acts of providing a notification of the presence of venous pulsation when detected.

22. One or more tangible, machine readable media, comprising code executable to perform the acts of:

deriving a metric of the pulse shape of one or more plethysmographic signals;

deriving a phase comparison of the plethysmographic signals; and

detecting the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

23. The tangible, machine readable media of claim 22, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

24. The tangible, machine readable media of claim 22, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

25. The tangible, machine readable media of claim 22, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period time of the one or more plethysmographic signals.

26. The tangible, machine readable media of claim 22, further comprising code executable to perform the acts of combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

27. The tangible, machine readable media of claim 26, further comprising code executable to perform the acts of comparing the venous pulsation metric to a threshold value.

28. The tangible, machine readable media of claim 22, further comprising code executable to perform the acts of providing a notification of the presence of venous pulsation when detected.

29. A patient monitoring system comprising:

a patient monitor configured to;

derive a skew metric for one or more plethysmographic signals; and

detect the presence of venous pulsation based on the skew metric.

30. The system of claim 29, wherein the patient monitor is configured to process the skew metric to compensate for the typical rate-dependent changes in the skewness of arterial waveforms.

31. The system of claim 29, wherein the patient monitor is configured to adjust the skew metric based on pulse rate.

32. The system of claim 29, wherein detecting the presence of venous pulsation comprises:

deriving a skew of the plethysmographic signal after filtering with a first set of filters; and

comparing the skew metric to the skew of the plethysmographic signal after filtering with a second set of filters.

33. The system of claim 29, wherein the patient monitor is configured to provide a notification of the presence of venous pulsation when detected.

34. A patient monitoring system comprising:

a patient monitor configured to;

derive a metric of the pulse shape of one or more plethysmographic signals;

derive a phase comparison of the plethysmographic signals; and

detect the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

35. The system of claim 34, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

36. The system of claim 34, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

37. The system of claim 34, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period time of the one or more plethysmographic signals.

38. The system of claim 34, wherein detecting the presence of venous pulsation comprises combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

40. The system of claim 34, wherein the patient monitor is configured to provide a notification of the presence of venous pulsation when detected.

39. The system of claim 39, wherein detecting the presence of venous pulsation comprises comparing the venous pulsation metric to a threshold value.

41. A patient monitoring system comprising:

a patient monitor configured to;

derive a ratio of a minima-to-maxima time over an entire pulse period time of one or more plethysmographic signals; and

detect the presence of venous pulsation based on the ratio.